I had a co-op job where I actually had to dress up. I picked up a few pairs of these when I went shopping for some better clothes for the job.
Turned out to be a wise decision. The job I had was at a school (basically as a student teacher) and although I could sit in the teachers lounge for lunch, they were all 40 and the students were my age, so I sat with them -- they were pretty cool. Someone stepped on a ketchup packet and it shot onto my pants. I grabbed a napkin and wiped it right off. You couldn't even tell it happened. Well worth the extra few bucks on pants than looking like an ass with a ketchup stain on my pants standing in front of my students.